Loneliness and Serious Illness

Loneliness and social isolation take a substantial toll on the human body, researchers say, in some frightening ways. But they are beginning to find out exactly why that is.

Studies show that people who are chronically lonely have significantly more heart disease, are more vulnerable to metastatic cancer, have an increased risk of stroke and are more likely to develop neurodegenerative diseases such as Alzheimer’s. They also are 25 percent more likely to die prematurely.

Researchers estimate that some 60 million Americans — one fifth of the population — suffer from the pain of loneliness. And with millions of baby boomers now facing a radically shrinking social world as they retire from the workplace, see their children disperse, lose friends and family members to illness and death, the rising tide of loneliness has all the hallmarks of a widespread and costly epidemic.

“Our culture is changing in ways that invite us — in fact, almost require us — to be more lonely and disenfranchised,” says Steve Cole, professor of medicine and psychiatry and biobehavioral sciences in the David Geffen School of Medicine at UCLA and director of the UCLA Social Genomics Core Laboratory.

Cole studies the effects of loneliness at the molecular level, a deep dive made possible by the Human Genome Project. He began the work in the early 2000s, after a study revealed that closeted gay men with HIV died at a significantly faster rate than gay men with HIV who were open about their sexuality. The reason, it turned out, was the immune systems of the closeted men were not as robust as those of the openly gay men. Closeted men were far more sensitive to social threats, such as being rejected or even ostracized for their sexuality, than openly gay men.

“The question became, is there something about threat-sensitivity that might make our bodies work differently?” Cole says, according to a UCLA news release. “And that concept turned out to be a very productive key to the biology of how loneliness turns into disease.”

Working with John Cacioppo, founder and director of the Center for Cognitive and Social Neuroscience at the University of Chicago, Cole studied how gene expression in a small group of lonely people differed from a group of non-lonely people. The results were startling.

“We found the key antiviral response driven by so-called Type 1 interferon molecules was deeply suppressed in the lonely people relative to the non-lonely people,” Dr. Cole says. “But we also found that there was another block of genes that was not suppressed — in fact, it was greatly activated — and this block of genes was involved in inflammation.”

Inflammation fuels disease processes in a host of devastating illnesses, including atherosclerosis, Alzheimer’s and cancer, Cole explains. Inflammation is not the disease itself; rather, it serves as a kind of molecular fuel that helps the disease thrive and grow. The study revealed that not only are lonely people markedly more vulnerable to outside threats such as viruses and bacteria, they also are under attack from within by their own bodies. But why?

“The best theory is that this pattern of altered immunology is a kind of defensive reaction mounted by your body if it thinks you are going to be wounded in the near future,” Cole says.